Collaborative Research: The Influence of Sponge Holobiont Metabolism on Coral Reef Dissolved Organic Matter and Reef Microorganisms

合作研究：海绵全生物代谢对珊瑚礁溶解有机物和珊瑚微生物的影响

• 批准号: 1924540
• 负责人: Cara Fiore
• 金额: $ 66.71万
• 依托单位: Appalachian State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-15 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1924540&HistoricalAwards=false
• 关键词: Collaborative; Research; Influence; Sponge; Holobiont

The seawater around coral reefs is typically low in nutrients, yet coral reefs are teeming with life and are often compared to oases in a desert. Life exists in these 'marine deserts' in large part, due to symbiotic associations between single-celled microbes and invertebrates such as corals and sponges. The concentration and type of dissolved organic matter (DOM), a complex pool of organic nutrients such as amino acids, vitamins, and other diverse compounds, also affects the health of coral reefs. The composition of DOM on coral reefs is linked to both the composition of free-living microbes in the seawater and to the nutrition of filter-feeding organisms, such as corals and sponges. However, the factors that influence the composition of DOM on coral reefs and the consequences of how it changes are not well understood. Recent work suggests that sponges could have a significant impact on the composition of reef dissolved organic nutrients, depending on sponge species due to differences in filtration capacity and in their symbiotic microbial communities. This project characterizes how diverse sponge species process DOM on coral reefs and determines the impacts of this processing on the free-living microbial community. Seawater is collected from sponges (pre- and post- sponge filtration) on coral reefs in the relatively pristine region of Curacao, and incubation experiments measure the impact of sponge filtration on the growth of the free-living microbial community. The organic nutrients of seawater samples are analyzed using cutting-edge techniques to distinguish the types of nutrients that are processed by sponges. The incubation experiments, using free-living microbes collected from the coral reef, quantify the impact of sponge filtration on the growth and composition of this community. This project provides fundamental understanding of how sponges contribute to the base of the coral reef food web. As the human-driven impacts continue to alter the composition of organisms on reefs, this understanding is necessary to predict changes to reef microbial food webs and is thus essential for scientists, reef managers, and policy decision makers. This project trains undergraduate students and a postdoctoral scholar and contributes to undergraduate and K-12 education through development of sponge-centric lessons that focus on local U.S. east coast aquatic environments as well as coral reef ecosystems. Sponges vary in their capacity to filter seawater and in their associated microbial communities, leading to diverse metabolic strategies that often coexist in one habitat. While it is well-established that sponges are important in processing dissolved organic matter (DOM), an important reservoir of reduced carbon compounds, and transferring this energy to benthic food webs, there has been limited work to understand the consequences of sponge processing on the composition of coral reef DOM and on pelagic food webs. Specifically, while studies have shown that exudates of corals and algae select for specific groups of picoplankton (autotrophic and heterotrophic, respectively), similar data for sponges are required to understand the multiple factors that shape the composition of DOM and of the picoplankton community on coral reefs. Thus, this project is aimed at addressing a major knowledge gap of the role of sponge-derived DOM (sponge exometabolome) in coral reef biogeochemistry. An in situ sampling design targeting prominent Caribbean sponges and picoplankton incubation experiments is coupled to address both the composition of sponge exometabolomes and delineate shifts in the picoplankton community derived from sponge exometabolomes. Molecular-level changes to seawater DOM by sponge processing and the impact of these changes on the overall coral reef DOM profile is assessed with two DOM analysis techniques: a commonly used fluorometry technique (fDOM analysis) and with high-resolution mass spectrometry (LC-MS/MS). Additionally, microbiome and functional gene profiling, growth metrics, and nutrient analyses are employed to assess changes in the picoplankton community in response to sponge exometabolomes. Advanced data analysis techniques then synthesize data generated by each approach to provide novel insight on a poorly uncharacterized biogeochemical pathway on coral reefs. The work outlined here represents entirely novel information on the impact of sponge metabolism on the composition of DOM, sheds light on biologically important molecules involved in benthic-pelagic coupling, and importantly, generates data using standardized methods, thus facilitating comparison to previous and future DOM datasets.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

珊瑚礁周围的海水通常营养成分较低，但珊瑚礁却充满了生命，经常被比作沙漠中的绿洲。生命在这些“海洋沙漠”中存在很大程度上是由于单细胞微生物与珊瑚和海绵等无脊椎动物之间的共生关系。溶解有机物（DOM）的浓度和类型，一个复杂的有机营养素库，如氨基酸，维生素和其他不同的化合物，也影响珊瑚礁的健康。珊瑚礁上DOM的组成与海水中自由生活的微生物的组成和滤食性生物（如珊瑚和海绵）的营养有关。然而，影响珊瑚礁上DOM组成的因素及其变化的后果还没有得到很好的理解。最近的工作表明，海绵可能有一个显着的影响，珊瑚礁溶解有机营养物质的组成，取决于海绵物种，由于过滤能力和共生微生物群落的差异。该项目描述了不同海绵物种如何处理珊瑚礁上的DOM，并确定了这种处理对自由生活的微生物群落的影响。海水收集海绵（前和后海绵过滤）的珊瑚礁在相对原始地区的库拉考，和培养实验测量海绵过滤的影响，对自由生活的微生物群落的增长。使用尖端技术分析海水样品的有机营养素，以区分海绵处理的营养素类型。孵化实验，使用从珊瑚礁收集的自由生活的微生物，量化海绵过滤对这个社区的增长和组成的影响。该项目提供了海绵如何对珊瑚礁食物网的基础做出贡献的基本理解。由于人类驱动的影响继续改变珊瑚礁上生物的组成，这种理解对于预测珊瑚礁微生物食物网的变化是必要的，因此对于科学家，珊瑚礁管理者和政策决策者至关重要。该项目培训本科生和博士后学者，并通过开发以海绵为中心的课程，重点关注当地美国东海岸水生环境以及珊瑚礁生态系统，为本科生和K-12教育做出贡献。海绵过滤海水的能力及其相关的微生物群落各不相同，导致多种代谢策略通常共存于一个栖息地。虽然海绵在处理溶解有机物（一个重要的还原碳化合物储存库）和将这种能量转移到海底食物网方面发挥着重要作用，但了解海绵处理对珊瑚礁溶解有机物组成和远洋食物网的影响的工作有限。具体而言，虽然研究表明，珊瑚和藻类的分泌物选择特定群体的微型浮游生物（分别为自养和异养），海绵需要类似的数据，以了解多种因素，形状的DOM和微型浮游生物群落的珊瑚礁的组成。因此，该项目旨在解决海绵衍生DOM（海绵外代谢组）在珊瑚礁生物地球化学中的作用的主要知识差距。一个在原地采样设计，针对突出的加勒比海海绵和微型浮游生物孵化实验耦合到海绵exometabolomes和描绘的变化，在微型浮游生物群落来源于海绵exometabolomes的组成。分子水平的变化，海水DOM海绵加工和这些变化对整体珊瑚礁DOM配置文件的影响进行了评估与DOM分析技术：一个常用的荧光技术（fDOM分析）和高分辨率质谱（LC-MS/MS）。此外，微生物组和功能基因分析，生长指标和营养分析，以评估在微型浮游生物群落响应海绵exometabolomes的变化。先进的数据分析技术，然后综合每种方法产生的数据，以提供新的见解，对珊瑚礁的一个很差的非生物地球化学途径。这里概述的工作代表了海绵代谢对DOM组成的影响的全新信息，揭示了参与底栖-浮游耦合的生物重要分子，重要的是，使用标准化方法生成数据，该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识产权进行评估来支持。优点和更广泛的影响审查标准。